In my stash of discarded bits I have these two ...

... left over from the Heywood Ursulike builds, so I found a few prototype dimensions - mainly length - and a square-on side view photo, and made a rough drawing using the hoods of the two bodies to get the proportions. I think I'll take bits of the various types that appeal to come up with a composite body ...
I found a suitable chassis on eBay - "non-runner, spares or repair" ...

Spot the deliberate mistake? The wire from the pick-ups is attached to the chassis. When I removed it and attached it to the near brush of the motor it ran - rather roughly, but it's a runner. So it was stripped down and cleaned, the coupling rods were straightened, the big sticky-up lump at the front was hacked off, couplings removed, and PTFE grease applied all round. The motor's coil has some 5mm slop - the gear is well forward on the shaft - so I found a spare -04 motor in the stash, cleaned the commutator and fitted new brushes ...

... and ended up with this. When power was applied it ran, and gradually got freer running after about 10 seconds, so I reckon I have the chassis ready. Now the bodies are marinating in an undiluted Dettol bath ready for surgery ...
Hours of fun ...